Why are bats dying in droves?

Little brown bat with fungus on muzzle.

Bats are typically considered scary animals (what would Halloween be without them?) but really we should love them. Bats eat bugs. Lots and lots of bugs. And they pollinate plants and spread their seeds around.

Little brown bats in NY hibernation cave. Note that most of the bats exhibit fungal growth on their muzzle.

Unfortunately, bats in some spots across the northeastern United States have been dying off for the last two years, and bat-lovers are worried. The actual cause is still a mystery, but scientists have recently learned some important lessons about the fungus that is somehow involved in the die-offs.

Researchers have called the bats' condition "white-nose syndrome," because of this white fungus that grows on the afflicted animals' muzzles, ears and wings. If scientists can figure out how the fungus involved in white nose syndrome, they would be closer to figuring out how to prevent the die-offs from happening.

David Blehert of the United States Geological Survey's Natioanl Wildlife Health Center and colleagues took samples of fungus from over 100 bats, of several species, afflicted with white-nose syndrome.

By growing the fungus in the lab, the researchers discovered it prefers to grow at cold temperatures. Warmer temperatures inhibit the infection. A genetic analysis suggested that the fungus belongs to the Geomyces genus, which includes other species that colonize the skin of animals in cold climates.